Joint having force converting means

ABSTRACT

A joint comprising two parallel walls, one of which has a through hole aligned with a cavity in the other wall, and a fastening device extended through said hole and into said cavity to engage force-converting means whereby one wall is pulled radially toward the other and simultaneously moved parallel thereto.

States atent 1191 Estliclt Dec. 25, 1973 [54] JOINT HAVING FORCECONVERTING 1,200,798 10/1916 Bennett 285/71 MEANS 1,827,257 10/1931Parker 285/339 x 2,991,091 7/1961 DeCenzo 285/83 [75] Inventor: Raymond.1- Esth k, m t 3,148,902 9/1964 Gardner et a1 285/339 'Mass. 2,643,9016/1953 Manoogian 285/403 r 2,793,779 5/1957 Woods 285/330 X [73]Asslgneei Raythem Cmnpany, Lexmgtonr 2,945,704 7/1960 Korn 285/330 xMass 3,472,538 10/1969 Vincent et a1. 285/421 X [22] Filed: Sept. 30,1970 Przmary Examiner-Dennis L. Taylor 1 1 pp N04 761844 Attorney-HaroldA. Murphy and Joseph D. Pannone 52 us. (:1. 285/339, 285/404 1 1ABSTRACT [51 1111:. C1. F161 19/06 A joint comprising two parallelwalls, one of which has [58] Field of Search 285/339, 71, 83, a throughhole aligned with a cavity in the other wall, 285/403, 404, 421, 214,341, 330 and a fastening device extended through said hole and into saidcavity to engage force-converting means [56] References Cited wherebyone wall is pulled radially toward the other UNITED STATES PATENTS andsimultaneously moved parallel thereto.

385,287 6/1888 Story 285/339 2 Claims, 9 Drawing Figures PATENTEDUEB 25ms SL781. 042

sum 2 0F 2 JOIINT HAVING FORCE CONVERTING MEANS BACKGROUND OF THEINVENTION This invention is related, generally, to joint structures andis concerned, more particularly, with a joint for coupling colineartubular members of streamlined cylindrical bodies.

Generally, colinear tubular members, such as adjacent portions of apipeline, for example, are joined end to end by means of external orinternal annular flanges which extend radially from abutting ends of themembers. Each joint comprises a pair of juxtaposed flanges which arecoupled to one another usually by bolts extending through respectivealigned apertures in the flanges and engaging nuts on the far side. If aflanged joint is to be hermitically sealed, the interfacing flatsurfaces of the juxtaposed flanges usually are machined smooth and aflat-faced gasket is positioned therebetween. Consequently, when thecoupling bolts and nuts are tightened, the juxtaposed flanges are drawnaxially toward one another, and the gasket is compressed annularlytherebetween, thereby forming a compact hermetically sealed joint. Thus,the radially flanged joint is structurally rigid and provides fullannular compression of the interposed gasket material.

However, in some instances, external radial flanges cannot be used forcoupling colinear tubular members. In missile and space applications,for examples, tubular shell portions of streamlined cylindrical vehiclesmust be jointed end to end in a manner which will minimize aerodynamicdrag. On the other hand, the high acceleration forces associated withlaunching and the severe environmental conditions encountered duringflight are two of the many reasons why the body joints of these vehiclesmust be provided with the structural rigidity and full annularcompression characteristics of externally flanged joints. Internalflanges can be coupled as described only when the internally flangedjoints are accessible from opposing ends of the resulting tubularstructure. Unfortunately, the tubular shell sections of missiles andspace vehicles, generally, are preloaded with component parts, such aspropulsion and navigational subassemblies, for examples. Therefore,internal radially flanged joints do not provide a feasible means forjoining these preloaded shell sections end to end. Another methodcommonly employed for joining colinear tubular members comprises havingrespective male and female end portions of adjoining members slidablyengaged in telescoping relationship. In order to seal these telescopicjoints, one of the opposing surfaces of each joint, generally, isprovided with a respective radial groove wherein there is disposed aresilient 0" ring having an annular portion protruding out of thegroove. Accordingly, an annular clearance is provided between therespective male and female end portions to facilitate assembly and toensure that the interposed protruding portions of the 0" rings will beslidably engaged during telescopic engagement of the end portions andcompressed into the associated radial grooves. To achieve the structuralrigidity and full annular compression required, threaded portions ofangularly spaced screws, generally, are passed through respectiveradially aligned apertures in the overlapping wall portions of eachjoint and engage respective nuts or like fastening devices affixed tothe inner surfaces of the respective male members. Thus, this methoddoes 'not require access to the interior of the resulting tubularstructure.

However, it has been found that when the radially extending screws ofsuch telescopic joints are tightened, the female wall portions generallybuckle or scallop in localized areas around the respective screws. Theunderlying cause of this distortion is related to the annular clearancesprovided between the male and female wall portions of the respectivejoints in order to facilitate assembly and to accommodate the protrudingportions of the associated 0" rings. As a result, the female wallportions cannot be compressed circumferentially to meet the concentricmale wall portions. Consequently, the respective O ring seals are notcompressed annularly into the associated radial grooves, and theresulting seals are of questionable value. Furthermore, the radiallyextending screws of these telescopic joints are required to withstandany axially directed forces acting on the resulting cylindricalstructure, such as the acceleration forces associated with launching,for example. Thus, the structural rigidity of these joints is dependentupon the beam strength of the respective radially extending screws andthe number of screws used to couple each of the respective joints.Therefore, these telescopic joints do not possess the structuralrigidity and full annular compression characteristics of externallyflanged joints.

SUMMARY OF THE INVENTION Accordingly, this invention provides means forcoupling colinear tubular members whereby the resulting joints have thestructural rigidity and full annular compression characteristics ofexternally flanged joints. Furthermore, this objective is achieved in amanner which does not require access into the interior of the resultingtubular structure. This inventive means comprises two tubular membershaving adjoining end portions slidably engaged in telescopingrelationship, the female member having an internal annular flangelocated adjacent the open end of the male member and in axial alignmentwith an annular portion thereof. The flange is provided with an annularrecess facing the open end of the male member and disposed in the recessis a resilient O ring having an annular portion protruding from therecess.

An annular series of angularly spaced holes extend through the wall ofthe female member, adjacent the open end thereof, which holes areradially aligned with respective tapped holes of elongated inserts whichare slidably disposed in the wall of the male member and at a obliqueangle with the wall of the female member. Thus, a wedge-shaped wall isdisposed between each elongated insert and the adjacent wall portion ofthe female member. Threaded members extend through respective holes inthe female member and are journalled into the radially aligned tappedholes of associated inserts. Consequently, the inserts are pulledagainst the interposed wedge-shaped walls and up the adjacent slopedsurfaces thereof whereby bidirectional pressure forces are developedwhich pull the walls of the male and female members radially toward oneanother and move the male and the female members axially relative to oneanother. As a result, the O ring is compressed into the supportingannular recess and the associated flange butts against the open end ofthe male member, thereby providing a hermetically sealed joint havingthe structural rigidity characteristic of externally flanged joints.

The slidable inserts may be slidably disposed in respective cavitieswhich extend into an internal annular flange of the male member, asshown in one embodiment. Also, the inserts may be slidably disposed inrespective housings of captive fastener assemblies, as shown in onealternative embodiment. Furthermore, the inserts may be slidablydisposed in respective housings of anchor fastening devices, as shown inanother alternative embodiment.

BRIEF DESCRIPTION OF THE DRAWING For a more complete an understanding ofthis invention reference is made to the drawings wherein:

FIG. I is a side elevational view, partly in axial section, of ssreamlined cylindrical body embodying the joint structure of thisinvention;

FIG. 2 is an enlarged, fragmentary, axial sectional view of the jointstructure just before the hermetical seal is formed.

FIG. 3 is an enlarged, fragmentary, axial sectional view of the jointstructure after the hermetic seal is formed;

FIG. 4 is a sectional view taken along the line 4--4 of FIG. 3 andlooking in the direction of the arrows;

FIG. 5 is a diagrammatic illustration of th forces produced when formingthe joint structure of this invention;

FIG. 6 is an enlarged, fragmentary, axial sectional view of analternative embodiment of the coupling means;

FIG. 7 is a cross-sectional view taken along the line 7--7 of FIG. 6 andlooking in the direction of the arrows;

FIG. 8 is an enlarged, fragmentary, axial sectional view of anotheralternative embodiment of the coupling means; and

FIG. 9 is a cross-sectional view taken along the line 99 of FIG. 8 andlooking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing whereinlike characters of reference designate like parts throughout the severalviews, there is shown in FIG. 1 streamlined cylindrical body 11, such asa missile, for example, which includes two colinear tubular members, 10and 12 respectively, having adjoining end portions, 14 and 16respectively, slidably engaged in telescoping relationship to form ajoint 18 therebetween. As shown more clearly in FIG. 2, end portion 14which comprises an externally reduced diameter portion of tube 10,constitutes the male member of the joint 18 and the overlapping wallportion 16 of tube 12 constitutes the female member.

The male end portion 14 terminates a predetermined axial distance fromthe open end thereof in an external annular shoulder 20 formed by thejuncture of end portion 14 with the full diameter portion of tube 10.The female end portion 16 terminates a predetermined axial distance fromthe open end thereof in an internal annular flange 22 which isintegrallyjoined to the cylindrical wall of tube 12 and extends radiallyinward therefrom. Flange 22 has a flat end surface 23 which is machinedsmooth and provided with an annular recess 24 of predetermined depth.Installed in recess 24 is an 0" ring 26 of resilient material, such asrubber, for example, and of predetermined thickness such that an annularportion ofO" ring 26 protrudes out of the recess 24.

The wall of male portion 14 is thickened on the inner side thereof toprovide an annular flange 28 which, preferably, extends a greater radialdistance inwardly of tube 10 than flange 22 extends inwardly of tube 12and has a flat, smooth annular surface 29 which is located normallyadjacent and in axial alignment with the O ring 26 when the male portion14 is slidably engaged with the female portion 16. Consequently, whenthe male member 14 is fully engaged with the female member 16, as shownin FIG. 3, the surface 29 of flange 28 presses the protruding portion ofO ring 26 into the recess 24 and butts against the surface 23 of flange22, thereby achieving the full annular compression and structuralrigidity characteristics of an internal radially flanged joint. Thus,the joint 18 has the structural features of a telescopic joint and aninternally flanged joint. However, it should be noted that in order tohave the surface 29 of flange 28 butt against the surface 23 of flange22 before the open end of female member 16 contacts the external annularshoulder 20, the axial length of the male member 14 must be slightlygreater than the axial length of the female member 16.

The flange 28 is provided with an angularly spaced series of cylindricalcavities 30, each having an elliptical opening in the outer peripheralsurface of male member 14 and extending into flange 28 at a uniformoblique angle with the longitudinal axis of male member 14. Thus, thereis axially disposed between each cavity 30 and the outer peripheralsurface of male member 14 a respective wedge-shaped wall 32 having asloped inner surface 33 which constitutes a longitudinal portion of thewall surrounding the respective cavity and having a tapered thin edgeportion which is disposed adjacent the elliptical opening of saidcavity. An axially extending keying pin 40 is mounted in the flange 28opposite each sloped surface 33, the pins extending beyond the surfaces33 into the cavities 30. In each cavity 30, there is slidably disposed arespective insert 36 which comprises a cylindrical slug of relativelyhard rigid material such as steel, for example, and has a predeterminedlength. Each insert 36 has a longitudinal slot 38 which slidablyreceives the protruding portion ofa respective keying pin 40. Thus, thepins 40 and cooperating slots 38 restrain rotational movement of therespective inserts 36 but permit longitudinal movement in the associatedcavities 30.

The inserts 36 lie beyond the plane of the openings in the respectivecavities 30 and disposed in the surface of each end portion 37 thereofis an open end of a respective tapped hole 42 which extends into theassociated insert 36 at an oblique angle with the longitudinal axisthereof. When oriented by the respective keying pin 40 and cooperatingslot 38, the associated tapped hole 42 is disposed substantiallyperpendicular to the outer peripheral surface of male member 14 andtransverse to the longitudinal axis thereof. Thus, it can be seen thatthe oblique angle formed by the tapped hole 42 with the longitudinalaxis of the associated insert 36 is the complement of the oblique angleformed by the associated cavity 30 with the longitudinal axis of malemember 14. Radially aligned with each tapped hole 42 is a respectivehole 44 in the encircling wall of the female member 16. Machine screws46 extend radially through the respective holes 44 and into holes 42,thereby threadingly engaging the respective inserts 36.

When a screw 36 is journalled into a hole 42, the associated insert 36is pulled against the adjacent sloped surface 33 of the wedge-shapedwall 32. As illustrated in FIG. 5, the pressure exerted by the insert 36against the wedge-shaped wall 32 may be represented by a force vector 48which can be resolved into two orthogonally directed force vectors, 50and 52 respectively. The force vector 50 represents that component ofthe pressure exerted by insert 36 which is directed radially outward andperpendicular to the overlapping wall portions of the male and femalemembers, 14 and 16 respectively. The force vector 52 represents thatcomponent of the pressure exerted by insert 36 which is directed axiallytoward the open end of male member 14 and parallel to the overlappingwall portions of the male and female members, 14 and 16 respectively.Thus, it can be seen that the respective magnitudes of the axially andradially directed component forces is dependent upon the angle of theslope surface 32.

In response to the radially directed component of the pressure, which isrepresented by vector 50, the adjacent wall portions of the male member14 and the female member 16 are drawn radially toward one another, asindicated by the component force vector 50 and the reactive force vector54. In response to the axially directed component of the pressure, whichis represented by vector 52, the adjacent wall portions of the malemember 14 and the female member 16 are moved axially relative to oneanother, as indicated by the component force vector 52 and the reactiveforce vector 56. The resulting relative radial and simultaneous axialmovements of the adjacent wall portions of the male member 14 and thefemale member 16 permit the tapped hole 42 to travel radially outwardalong the threaded shaft of the screw 44 thereby drawing the associatedinsert 36 longitudinally up the adjacent sloped surface 33 whilemaintaining the pressure against the interposed wedge-shaped wall 32.Thus, the engaged insert and the associated wedge-shaped wall 32 convertthe unidirectional tension force exerted by the screw 46 into abidirectional pressure force.

in practice, the female member 16 is made to slidably engage the malemember 14 until the through holes 44 in the female member are radiallyaligned with respective tapped holes 42 of the inserts 36. At this time,the flat surface 2% of flange 28 may be just contacting the protrudingportion of 0" ring 26. The screws 46 are inserted through the holes 44and journalled incremental distances into the aligned tapped holes 42.Continuous sequential journalling of the respective screws 46 draws theengaged inserts 36 up the associated sloped surfaces 32 and moves themale member 14 and the female member 16 axially relative to one another.However, before any of the inserts 36 can contact the wall of femalemember 16 or the open end of the female member can bear against theexternal shoulder 20, the 0" ring 26 is compressed into the-recess 24and the surface 23 of flange 22 butts against the surface 29 of flange28. Thus, the reason for having each insert 36 a predetermined length isto ensure that when the associated tapped hole 42 is engaged by arespective screw 46, the insert 36 will be spaced the proper distancefrom the wall of the female member 16, as measured along the associatedsloped surface 32.

The radially extending screws 46 serve to hold the walls of the members14 and 16 radially against one another and to hold the surface 23 offlange 22 against the surface 29 of flange 28. However, the screws 46are not required to withstand axially directed forces as in conventionaltelescopic joints. In the joint- 18, axially directed forces areresisted by the juxtaposed flanges 22 and 28, respectively. Thus, thejoint 18 provides the structural rigidity and full annular compressioncharacteristics of internally flanged joints but does not require accessto the interior of the resulting tubular structure in order to couplethe juxtaposed flanges 22 and 28. The joint 18 is coupled from theexterior of the resulting tubular structure by means of the radiallyextending screws 46 developing bidirectional pressure forces which pullthe juxtaposed flanges 22 and 28 axially toward one another and whichdraw the walls of the male and female members radially toward oneanother.

The heads of the screws 46 are countersunk into the wall of the femalemember 16 in order to preserve the streamline characteristics of thecylindrical body 11. For the same reason, the open end of the femalemember 16 is designed to approach the external shoulder 20 as close aspossible without bearing against it before the surface 23 of flange 22butts against the surface 29 of flange 28. Alternatively, a recess,similar to recess 24, for example, could be provided in the annularshoulder 20 and an O ring, such as 36, for example, could be disposed inthe recess with an annular portion of the 0" ring protruding therefrom.Thus, the open end of female portion 16 would press the protrudingportion of the O ring into the supporting recess and thereby establish aseal at the open end of the female member 16. If greater torque power isrequired to move the male and female members axially relative to oneanother as described, the screws 46 could be replaced by bolts havinggreater beam strengths and heads which are rotated by socket typewrenches, for example. Also, the inserts 36 need not be supported in acontinuous annular flange but may be disposed in respective angularlyspaced bosses which may be cast or otherwise affixed to the innersurface of the male member 14. Alternatively, the suggested bosses maybe provided in the form of respective captive fastener assemblies, asshown in FIGS. 69, for examples.

FIG. 6 shows the female member 16 slidably engaged in telescopingrelationship with a male member 60, which is similar to male member 14except the internal flange 28 is omitted. Axially spaced from the openend of male member 60 is a series of angularly spaced holes 62 whichextend through the wall of the male member. Disposed on the innersurface of male member 60, in radial alignment with each hole 62, is arespective captive nut assembly 64. Each captive nut assembly isprovided with an arcuately curved surface 66 which conforms to the wallof male member 60 and comprises one side of a housing 68 which projectsinwardly of the male member. The housing 68 is provided with an annularflange 70 which is securely attached, as by welding, for example, to theadjacent inner surface of male member 60.

Centrally located in the surface 66 of housing 68 is an opening ofacavity 72 which, as shown in FIG. 7, has a rectangular cross-section andextends into the housing 68 at an oblique angle with the surface 66 ofthe housing. Thus, disposed between the surface 66 and the cavity 72 isa wedge-shaped wall 74 having a sloped inner surface 76 which forms alongitudinal portion of the wall surrounding the cavity 72.Longitudinally disposed in the opposing side of the cavity 72 is aslotted keyway 78 which terminates at one end adjacent the opening ofcavity 72. Slidably disposed in the keyway 78 is a generally U-shapedspring clip 80 having upright tabs 82 and 84 which hold a nut 86therebetween. An extended portion 85 of clip 80 butts against the end ofkeyway slot 78 adjacent the opening of cavity 72 to retain the nut 86within the housing 62. The nut 86 is provided with a tapped hole 88which is disposed perpendicular to the surface 66 of the housing 62 andin radial alignment with the associated hole 62 in male member 60. Themachine screws 46 which extend through respective holes 44 in the wallof the female member 16 pass through radially aligned holes 62 in malemember 60 and are journalled into respective tapped holes 88. Thus, itis readily apparent that the associated nuts will be pulled against theinterposed wedge-shaped walls 74 thereby producing the bidirectionalpressure force which will pull the walls of the male and female membersradially toward one another and will move the male and female membersaxially relative to one another.

FIGS. 7 and 8 illustrate how the nut 86 shown in FIG. 6 and 7 may beheld and oriented by a stamped metal housing 92 of an anchor nutassembly 90. Housing 92 comprises crossed metal arms, 93 and 94,respectively, which are integrally joined at one end to the base portionof a triangular shaped plate 95. The plate 95 has a hole 96 extendingtherethrough adjacent the base of the triangle and a V-shapedindentation transversely disposed adjacent the apex of the triangle. Thetapped hole 88 of the nut 86 is aligned with the hole 96 in plate 95 andthe crossed arms are wrapped loosely around the nut 86 to hold itagainst the adjacent sloped surface ofthe indentation 97. The plate 95is securely attached, as by welding, for example, to the inner surfaceof male member 60 such that the hole 96 and tapped hole 88 are radiallyaligned with the associated hole 62 in the male member 60. Thus, thetransverse half of indentation 97 adjacent the nut 86 forms the requiredwedgeshaped wall between the nut 86 and the wall of male member 60. Whenthe associated screw 46 extends through holes 44, 62 and 96 and isjournalled into the radially aligned hole 88, the nut 86 is pulledagainst-the adjacent sloped surface of the V-shaped indentation 97 andthereby produces the bidirectional pressure force which will pull thewalls of the male and female members radially toward one another andwill draw the male and female members axially relative to one another.

Thus, there has been disclosed herein means for coupling colineartubular portions of streamlined cylindrical bodies whereby the resultingjoints provide the structural rigidity and full annular compressioncharacteristics of internally flanged joints but do not require accessto the interior of the resulting cylindrical structure. Although theinserts 36 have been shown herein as having circular cross'sections,they may also have other cross-sectional configurations, such as square,for example, provided that the insert is longitudinally slidable alongan adjacent sloped surface. Furthermore,

this novel structure may be adapted for coupling hollow members havingother cross-sectional configurations than the circular one shown herein.For example, elongated hollow sections of air conditioning ducts, whichgenerally, have rectangular cross-sections, may be joined by use of thenovel joint structure disclosed herein. Moreover, this invention may beused wherever a fastening device is required to develop bidirectionalforces, such as instances where a joint is not accessible from onedirection but is accessible from an orthogonal direction, for example.

From the foregoing, it will be apparent that all of the objectives ofthis invention have been achieved by the structures shown and described.It will be also apparent, however, that various changes may be made bythose skilled in the art without departing from the spirit of theinvention as expressed in the appended claims. It is to be understood,therefore, that all matter shown and described is to be interpreted asillustrative and not in a limiting sense.

What is claimed is:

1. In combination:

first and second tubular members having respective first and second endportions slidably engaged in telescopic relationship, the first endportion having an inwardly extending flange and the second end portionhaving an end disposed in axial alignment with the flange;

said first end portion having in the wall thereof a series of spacedradially extending through holes;

said second end portion having in the outer surface thereof a series ofspaced openings, each opening being disposed in radial alignment with arespective one of said holes;

a plurality of first fastening devices, each disposed within arespective one of said holes and said radially aligned opening;

a plurality of cooperating second fastening devices,

each being disposed within said second end portion, in radial alignmentwith a respective one of said openings and engaged by a respective firstfastening; and

means affixed to the internal surfaces of the second end portion forslidably supporting each of said second fastening devices at an obliqueangle with the adjacent surface of said first end portion and includingtherebetween force converting means comprising respective wedge-shapedwalls for converting radially directed forces exerted by said firstfastening devices into bidirectional forces for moving the first andsecond end portions axially relative to one another while drawing thewalls thereof radially toward one another.

2. A combination as set forth in claim 1 wherein said supporting meanscomprises a series of spaced housings affixed to the internal surface ofsaid second end portion, each having a cavity therein disposed in radialalignment with a respective one of said openings and at an oblique anglewith the adjacent surface of said first end portion and having slidablydisposed therein a respective one of said second fastening devices.

1. In combination: first and second tubular members having respective first and second end portions slidably engaged in telescopic relationship, the first end portion having an inwardly extending flange and the second end portion having an end disposed in axial alignment with the flange; said first end portion having in the wall thereof a series of spaced radially extending through holes; said second end portion having in the outer surface thereof a series of spaced openings, each opening being disposed in radial alignment with a respective one of said holes; a plurality of first fastening devices, each disposed within a respective one of said holes and said radially aligned opening; a plurality of cooperating second fastening devices, each being disposed within said second end portion, in radial alignment with a respective one of said openings and engaged by a respective first fastening; and means affixed to the internal surfaces of the second end portion for slidably supporting each of said second fastening devices at an oblique angle with the adjacent surface of said first end portion and including therebetween force converting means comprising respective wedge-shaped walls for converting radially directed forces exerted by said first fastening devices into bidirectional forces for moving the first and second end portions axially relative to one another while drawing the walls thereof radially toward one another.
 2. A combination as set forth in claim 1 wherein said supporting means comprises a series of spaced housings affixed to the internal surface of said second end portion, each having a cavity therein disposed in radial alignment with a respective one of said openings and at an oblique angle with the adjacent surface of said first end portion and having slidably disposed therein a respective one of said second fastening devices. 